The present invention relates to a define for incremental control of at least one direct-current motor for a cooling fan of a motor vehicle.
Publication EP 1 017 158 A2 makes known a device for controlling the starting phase of a direct-current motor for a cooling fan of a motor vehicle, with which the speed of the direct-current motor can be varied in four stages using three resistors that can be connected in series using a relay. The device also includes a temperature-dependent switch for controlling the direct-current motor.
Furthermore, publication EP 0 445 015 A1 makes known a method for attaining different speed stages of a direct-current motor for a cooling fan via connection with several pairs of brushes. According to EP 518 538 A2, a continual speed adjustment is attained via control using pulse-width modulated (PWM) signals.